Information representing geographic features may be stored in databases and retrieved and manipulated using database management functions. Geographic features stored in databases are represented in either vector or raster format. For vector data, points are represented by their explicit x,y,z coordinates. Lines: are strings of points. Areas are represented as polygons whose borders are lines. This kind of vector format can be used to precisely record the location and shape of spatial objects. Instead of representing features by vector data formats, you can represent spatial objects by assigning values to the cells that cover the objects and record the cells as arrays, i.e. raster format. This kind of raster format has less precision, but is best for a lot of spatial analysis.
As a matter of fact, raster data (imagery and gridded data) is the dominant form of spatial information, which includes thematic maps, DEM/DTM, lattice data, remote sensing imagery, photogrammetric photos, scanned maps and graphs, geophysical images, medical images, etc.
Any spatial database management system must deal with the raster data type to provide a complete and efficient solution. Some general needs of broad application groups including:                Traditional GIS and remote sensing applications—users manage their geographic raster and gridded data assets using a scaleable, secure, and robust RDBMS for defense, intelligence, agriculture, natural resource management.        Business applications—leverage raster-based data in conjunction with other basic location data (address, etc.) to inventory and evaluate site locations and to track fixed and/or continuous assets. They include Asset Management and Facilities Management particularly in energy and utilities.        Image and Gridded Raster Data Repositories/Clearinghouses—support for clearinghouse servers that need to ingest, store, and disseminate very large volumes of geoimagery.        